This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Porous Layer Open Tubular (PLOT) chromatographic columns have been reported to have characteristics such as sensitivity and retention reproducibility superior to that of the packed bed solid phase RP columns. The 10um i.d. poly-(divinylbenzene-styrene) columns allow for higher diffusion rates than a typical packed column when used in biological molecule separation, which improves peak shape and chromatographic reproducibility. The present study is aimed at estimating such parameters loading capacity and robustness of the poly-(divinyl-benzene-styrene) PLOT columns and their comparison to traditional packed solid phase C-18 RP columns. The overall goal is to use PLOT columns in MudPIT setup for high complexity sample analysis.